rails-html-sanitizer: Possible XSS via shared scrubber state in concurrent calls

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-128069
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-13 18:17:34 UTC
Updated2026-11-13 18:17:34 UTC
Descriptionrails-html-sanitizer is responsible for sanitizing HTML fragments in Rails applications. Before 1.7.2, the HTML4 and HTML5 variants of Rails::HTML::SafeListSanitizer reuse one Rails::HTML::PermitScrubber across calls and mutate its tags and attributes without synchronization. In a multithreaded process, concurrent sanitize calls using different tags: or attributes: options can interleave and cause one call to use the other call's allowlist. If a permissive call admits a script element or event-handler attribute, output expected to be sanitized under a stricter policy can retain it and cause cross-site scripting when rendered. Applications that are single-threaded, use one identical allowlist everywhere, or provide a separate scrubber: are not affected. This issue is fixed in version 1.7.2.

Risk And Classification

Primary CVSS: v3.1 4.7 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

Problem Types: CWE-79 | CWE-362 | CWE-79 CWE-79: Improper Neutralization of Input During Web Page Generation | CWE-362 CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary4.7MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
3.1CNADECLARED4.7MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Rails Rails-html-sanitizer affected < 1.7.2 Not specified

References

ReferenceSourceLinkTags
github.com/rails/rails-html-sanitizer/releases/tag/v1.7.2 [email protected] github.com
github.com/rails/rails-html-sanitizer/commit/15f764c3563d5dd9b97ad32eaa7... [email protected] github.com
github.com/rails/rails-html-sanitizer/issues/228 [email protected] github.com
github.com/rails/rails-html-sanitizer/security/advisories/GHSA-h7wh-q2qr... [email protected] github.com
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